Operating
mode of the stabilizer of current on active and inductive loading
Abstract: the
scheme of the three-phase stabilizer of current allowing to receive the
three-phase stabilized current in loading irrespective of change in the set
limits of resistance of loading and the power supply is investigated.
Keywords: magnet,
ferroresonance, tiristor, current stabilizer, volt-ampere characteristic,
active and inductive loading, linear inductance, Larionov's scheme,
semiconductor rectifier.
The
majority of branches of electrical equipment, electrophysics, electrothermie,
galvanotechnics, needs automatic maintenance constancy of current at
simultaneous change of tension of three-phase food and the consumer's
resistance [1].
Such
tasks successfully decides with application magnetic, the ferrorezonansnykh and
thyristor stabilizers of current. I have these devices difficult electric
circuits and a form of a curve of the stabilized current of not sinusoidal. A
form of a curve of the stabilized current use filters of the highest harmonicas
to improvement.
In
Power supply chair Tashkent State Technical University inductance-capacitor
devices with a ferrorezonansny contour which possess property to stabilize
current to loading at broad change of three-phase entrance tension and
resistance of loading are developed.
In
this work the three-phase scheme of the ferrorezonansny stabilizer of current
having a sinusoidal form of a curve of the stabilized current is theoretically
and experimentally investigated.
In
fig.1. the schematic diagram of the offered three-phase ferrorezonansny
stabilizer of the current consisting from three parallel ferrorezonansny
contours included linear inductance and the condenser which is switched on in
parallel to this contour and collected according to the scheme of a triangle is
shown, and tops of this triangle is connected to a three-phase network through
active and inductive loading.
The analysis of
volt-ampere characteristics of separate sites of a chain showed that the
parallel ferrorezonansny contour included consistently with linear inductance
has "S" - the
figurative characteristic with a wide zone of negative site [2].
As showed experimental supervision, linear currents of i1,
i2, i3 remain stable in the wide range of
change of entrance tension and resistance of loading when the negative site of
"S" - the figurative characteristic of a ferrorezonansny
branch is compensated by the rectilinear characteristic of C12,
C23 and C13 condensers.
Three-phase
loading is connected consistently to the current stabilizer.
For
the analysis of the load mode we accept the following assumptions:
1. The dynamic curve of
magnetization of a ferromagnetic element is approximated by a power function of
a look [3];
2. Losses
on a hysteresis, vortex currents and active resistance are considered by
constant conductivity of g;
3. Streams of dispersion are neglected
and streams in linear elements aren't considered.
We enter the following designations:
- - impressed voltage;
- - the linear inductance which is consistently connected to a
parallel ferrorezonansny contour;
- - the condenser which is switched on in parallel to a ferromagnetic
element;
- - the condenser which is switched on in parallel to a ferrorezonansny
contour, switched on consistently with linear inductance;
- ; ; - currents proceeding through C31
condensers; C23 and C12;
- ; ; - the currents proceeding at triangle tops;
- ; ; - linear currents corresponding in phases 1, 2, 3;
- - the current proceeding through conductivity of g;
- - the current proceeding on a winding of a ferromagnetic element;
- - magnetic
flux in the core of a ferromagnetic element;
- - number
of rounds of windings of a ferromagnetic element.
The electric chain of the considered three-phase
ferrorezonansny stabilizer of current for active and inductive loading is
described by the following equations:
,
|
(1)
|
,
|
(2)
|
,
|
(3)
|
; ; .
|
(4)
|
Here,
.
|
(5)
|
(1)–(3) we will solve the equations by method of
the accounting of the main harmonica of a magnetic flux [3].
Let's say that:
.
|
(6)
|
When,
|
(7)
|
.
|
(8)
|
Considering (6)–(8) entering basic sizes after
reduction (1) to a dimensionless look we will receive:
,
|
(9)
|
,
|
(10)
|
The currents proceeding on contours:
Input basic sizes after reduction
(11) to a dimensionless look were received:
|
(14)
|
|
(15)
|
where,
For the basic size Фδ the value of a stream corresponding to a resonant
point of a ferrorezonansny contour is accepted. From (9), having set by various
Xm values, it is easy to construct the Уm=f(Xm).
On the basis of dependences (9), (10), (14) and
(15) we will construct the main characteristics of a chain in relative units
for various values of active and inductive loading at change of entrance
tension and resistance of loading. From the analysis of the received curves it
is visible that currents of i1, i2
and i3 in a wide limit of change of tension of a
network remain stable.
In fig.2. are submitted theoretical (1 - il1
at RH=20 Ohms, LH=0,12 Hz)
and experimental (2 - il1 at RH=20
Ohms, LH=0,12 Hz) adjusting characteristics.
The studied skilled stabilizer of current having the
following parameters:
С1=С2=С3=40 (mkF); L1=L2=L3=0,32 (Hz); g=1,21*10-3 (1/Ohm); К=6400*108; С12=С23=С31=20
(mkF); f=0,32 (Hz); ξ=0,88; δ=0,88; Uδ=380 (V); Iδ=2,3 (А).
Introduction to the scheme at the exit of the
device of the coordinating transformer and semiconductor rectifiers connected
according to Larionov's (fig.3) scheme allows to receive the stable
straightened current at the exit. Three-phase the ferrorezonansny stabilizer of
current with rectifiers can be used for receiving stable current for galvanic
electrolysis shops.
In the presence of the alternating current main
three-phase the ferrorezonansny stabilizer of current with rectifiers it can be
used for receiving stable current for charging of batteries charging stations.
In such devices tension necessary for charging
will be automatically established, depending on requirement, without
installation of special control devices.
Thus, three-phase the ferrorezonansny stabilizer
of current it is possible to consider as tension source converter in a current
source, not containing moving parts and contacts working beyond all bounds
long. These the device can be built practically on any current.
References:
1. A.N.Milyakh, I.V.Volkov,
Systems of invariable current on the basis of inductance-capacitor converters.
— Kiev: Naukova thought, 1974.
2. T.M.Kadyrov,
A.N.Rasulov, the Ferrorezonansny stabilizer of current with a sinusoidal form
of a curve of current. — Automatic equipment and telemechanics, 1977, № 11.
3. L.A.Bessonov, Nonlinear
electric chains. — M.: The higher school, 1964.
4. A.N.Milyakh, A.K.Shidlovsky, V.G.Kuznetsov,
Schemes of balancing of single-phase loadings in three-phase chains. — Kiev:
Naukova thought, 1973.
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